Recombinant Acetogenic Bacterium for Safe Methane Conversion
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Solution Overview
Problem
Current methods for industrial-scale growth of aerobic methanotrophs are hazardous due to the combustible nature of gaseous methane and oxygen substrates, and anaerobic methane oxidation by single microorganisms was previously considered biologically impossible, limiting the development of microorganisms capable of converting methane to useful products.
Innovation Solution
A recombinant acetogenic bacterium is developed that consumes methane and converts it into products using exogenous methane monooxygenase, nitrite reductase, and nitric oxide dismutase enzymes, derived from Methylomirabilis oxyfera, which allows for methane utilization without requiring a combustible gaseous substrate and produces oxygen internally for methane oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aerobic methanotrophs are used to convert methane to useful products, then methane conversion capability is achieved, but safety hazards increase due to the combustible nature of gaseous methane and oxygen substrates
Solution Approach 1:
The patent changes the physical state parameter of the substrate from gaseous (combustible methane-oxygen mixture) to aqueous (methane in water with acetogenic bacteria), eliminating the combustion hazard while preserving methane conversion capability through enzymatic action
Solution Approach 2:
The patent introduces water as an intermediary medium that dissolves methane and enables its conversion by acetogenic bacteria without requiring direct contact between gaseous methane and oxygen, thus preventing combustion while maintaining productivity
2Device complexity
If anaerobic methane oxidation is attempted by single microorganisms, then process simplicity is improved, but biological feasibility deteriorates as it was previously considered impossible
Solution Approach 1:
The patent makes the acetogenic bacterium universally capable of performing both anaerobic metabolism and methane oxidation through enzyme expression, allowing a single microorganism to fulfill multiple functions previously requiring separate organisms or impossible to achieve
Solution Approach 2:
The patent inverts the conventional understanding by making an anaerobic bacterium produce oxygen internally through nitrite reduction, then use that oxygen for methane oxidation - reversing the traditional aerobic/anaerobic dichotomy and enabling anaerobic methane oxidation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The recombinant bacterium efficiently converts methane into products such as ethanol, acetate, and other valuable compounds, providing a safer and more effective method for methane utilization and mitigation of greenhouse gas emissions.
Implementation Method 1
methane monooxygenase uses two reducing equivalents from NAD(P)H to split the O—O bond of O2, whereby one atom is reduced to water and the second atom is incorporated into the substrate to yield methanol: CH4+NAD(P)H+H++O2→CH3OH+NAD(P)++H2O
Implementation Method 2
M. oxyfera produces its own supply of oxygen by metabolizing nitrite via nitric oxide into oxygen and dinitrogen gas
Implementation Method 3
M. oxyfera produces its own supply of oxygen by metabolizing nitrite via nitric oxide into oxygen and dinitrogen gas
Data Source
AI summary
The invention provides a recombinant, acetogenic bacterium that consumes a substrate comprising CH4 and converts at least a portion of the CH4 to a product. In particular, the bacterium of may comprise one or more of exogenous methane monooxygenase (MMO), exogenous nitrite reductase (NIR), and exogenous nitric oxide dismutase (NOD). The invention further provides a method for producing a product comprising providing a substrate comprising CH4 to a culture comprising a recombinant, acetogenic bacterium, whereby the bacterium converts at least a portion of the CH4 to a product.